1. FIELD OF INVENTION
This invention relates generally to securing devices for chains, cables or the like and, more particularly, to adjustment, tightening and locking mechanisms for use with chains, cables or the like when securing heavy loads.
2. DESCRIPTION OF THE PRIOR ART
Chains and cables used in securing heavy loads in the transportation thereof are often prone to slipping and loosening which require that the driver of a truck carrying a heavy load stop and check the load at frequent intervals. Loads do come loose and may be discharged on the highway creating very serious traffic hazards which can create considerable dangers and accidents with the potential for great liability. One example of a prior art device is Huber, U.S. Pat. No. 2,848,259, which shows an elaborate complex rachet interlocking mechanism with a series of complex and very expensive members. Another example of the prior art is Billett, U.S. Pat. Nos. 2,321,001, which shows a turnbuckle lock having a member with one portion having a left handed thread and another portion having a right handed thread for adjusting the turnbuckle lock and a pin, of the cotter pin type, for locking the turnbuckle to a locking plate. Another example of the prior art is Methias, U.S. Pat. No. 1,286,701, which shows a turnbuckle with a left handed and right handed portion for accepting a left handed and right handed bolt and wings with cotter pins disposed therethrough and also through the bolts for locking into the turnbuckle body. Other examples of the prior art are Schubert, U.S. Pat. No. 2,367,740, and Stukenborg, U.S. Pat. No. 2,843,407. In the two patents which use cotter pins, U.S. Pat. Nos. 2,321,001 and 1,286,707, these cotter pins can easily become dislodged or broken off due to the large stress forces impressed upon turnbuckles in mobile service. Also, cotter pins once lost are difficult to find which would require that a constant supply be kept on hand to relock and replace the lost or broken cotter pins. Also, in the event as is quite common in mobilely transported loads, vibrations will tend to shift the cables or chains securing the loads, and therefore, create a slack condition which must be removed by the take up thereof by a driver or the railroad worker. In taking up the slack the cotter pins must be removed and possibly lost or broken therefore presenting a rather cumbersome and intricate problem in readjusting the loan as is required in the previous applications. U.S. Pat. No. 2,848,259 is very complex in requiring a great number of parts which are machined to close tolerances which may malfunction when becoming rusted. This problem applies especially to the rachet mechanisms thereof. The theft of loads from flat bed trucks is a continuing problem and any device which would increase the safety and security of such loads is an important consideration in the choice of load chain and cable take-up devices.